From a3eaa8649e4c6a6afdafaa04b9114fb230617bb1 Mon Sep 17 00:00:00 2001 From: Kai Huang Date: Wed, 4 Nov 2015 13:46:05 +0800 Subject: KVM: VMX: Fix commit which broke PML I found PML was broken since below commit: commit feda805fe7c4ed9cf78158e73b1218752e3b4314 Author: Xiao Guangrong Date: Wed Sep 9 14:05:55 2015 +0800 KVM: VMX: unify SECONDARY_VM_EXEC_CONTROL update Unify the update in vmx_cpuid_update() Signed-off-by: Xiao Guangrong [Rewrite to use vmcs_set_secondary_exec_control. - Paolo] Signed-off-by: Paolo Bonzini The reason is in above commit vmx_cpuid_update calls vmx_secondary_exec_control, in which currently SECONDARY_EXEC_ENABLE_PML bit is cleared unconditionally (as PML is enabled in creating vcpu). Therefore if vcpu_cpuid_update is called after vcpu is created, PML will be disabled unexpectedly while log-dirty code still thinks PML is used. Fix this by clearing SECONDARY_EXEC_ENABLE_PML in vmx_secondary_exec_control only when PML is not supported or not enabled (!enable_pml). This is more reasonable as PML is currently either always enabled or disabled. With this explicit updating SECONDARY_EXEC_ENABLE_PML in vmx_enable{disable}_pml is not needed so also rename vmx_enable{disable}_pml to vmx_create{destroy}_pml_buffer. Fixes: feda805fe7c4ed9cf78158e73b1218752e3b4314 Signed-off-by: Kai Huang [While at it, change a wrong ASSERT to an "if". The condition can happen if creating the VCPU fails with ENOMEM. - Paolo] Signed-off-by: Paolo Bonzini diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 2ac11641..5eb56ed 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -4718,8 +4718,9 @@ static u32 vmx_secondary_exec_control(struct vcpu_vmx *vmx) a current VMCS12 */ exec_control &= ~SECONDARY_EXEC_SHADOW_VMCS; - /* PML is enabled/disabled in creating/destorying vcpu */ - exec_control &= ~SECONDARY_EXEC_ENABLE_PML; + + if (!enable_pml) + exec_control &= ~SECONDARY_EXEC_ENABLE_PML; /* Currently, we allow L1 guest to directly run pcommit instruction. */ exec_control &= ~SECONDARY_EXEC_PCOMMIT; @@ -7804,7 +7805,7 @@ static void vmx_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2) *info2 = vmcs_read32(VM_EXIT_INTR_INFO); } -static int vmx_enable_pml(struct vcpu_vmx *vmx) +static int vmx_create_pml_buffer(struct vcpu_vmx *vmx) { struct page *pml_pg; @@ -7817,18 +7818,15 @@ static int vmx_enable_pml(struct vcpu_vmx *vmx) vmcs_write64(PML_ADDRESS, page_to_phys(vmx->pml_pg)); vmcs_write16(GUEST_PML_INDEX, PML_ENTITY_NUM - 1); - vmcs_set_bits(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_ENABLE_PML); - return 0; } -static void vmx_disable_pml(struct vcpu_vmx *vmx) +static void vmx_destroy_pml_buffer(struct vcpu_vmx *vmx) { - ASSERT(vmx->pml_pg); - __free_page(vmx->pml_pg); - vmx->pml_pg = NULL; - - vmcs_clear_bits(SECONDARY_VM_EXEC_CONTROL, SECONDARY_EXEC_ENABLE_PML); + if (vmx->pml_pg) { + __free_page(vmx->pml_pg); + vmx->pml_pg = NULL; + } } static void vmx_flush_pml_buffer(struct kvm_vcpu *vcpu) @@ -8706,7 +8704,7 @@ static void vmx_free_vcpu(struct kvm_vcpu *vcpu) struct vcpu_vmx *vmx = to_vmx(vcpu); if (enable_pml) - vmx_disable_pml(vmx); + vmx_destroy_pml_buffer(vmx); free_vpid(vmx->vpid); leave_guest_mode(vcpu); vmx_load_vmcs01(vcpu); @@ -8790,7 +8788,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) * for the guest, etc. */ if (enable_pml) { - err = vmx_enable_pml(vmx); + err = vmx_create_pml_buffer(vmx); if (err) goto free_vmcs; } -- cgit v0.10.2